Premixing photon-counting chirped amplitude modulation lidar for range and velocity measurement in photon starved scenes

A symmetric chirped amplitude modulation of the up-ramp and the down-ramp is implemented on the basis of previous work of premixing photon-counting chirped amplitude modulation lidar. This system is capable of obtaining the range and velocity of target simultaneously in photon starved scenes due to the high sensitivity of single-photon detectors. With the advantages of the premixing method this system breaks the limit of the maximum modulation frequency of the chirped amplitude modulation signal by the sampling rate of the Gm-APD and allows the use of much higher fundamental frequency and modulation bandwidth to improve the range and velocity detection accuracy. This paper demonstrates the working principle of this system, and analyzes the relationship of accuracy and system parameters from theory and experiment.